The present invention relates to a replaceable liquid filter, particularly for the lubricating oil of an internal combustion engine, with a filter element disposed between a feed opening and a discharge opening in a cup-shaped housing.
Replaceable liquid filters, which are also referred to as spin-on filters, are known in the art and generally comprise a cup-shaped housing with an end plate and a top plate which secures the end plate in place. The liquid to be filtered is supplied through feed openings formed in the end plate, which are arranged surrounding a concentrically disposed outlet opening. A hollow cylindrical filter element is disposed between the inlet and the outlet, and the inlet and the outlet each have a backflow check valve element. A backflow check valve membrane is disposed over the inlet openings, and a backflow check valve is arranged in the interior of the hollow cylindrical filter element. This prevents the filter element from running empty when the internal combustion engine is stopped.
A drawback of this known arrangement is that in replaceable liquid filters which are not arranged in a suspended manner, the liquid present above the backflow check valve and the liquid present in the groove-shaped supply channel of the cylinder head leaks out when the replaceable liquid filter is detached for servicing and thus contaminates the engine compartment and/or the environment.